Circulation
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Comparative Study
Lung water and urea indicator dilution studies in cardiac surgery patients. Comparisons of measurements in aortocoronary bypass and mitral valve replacement.
We measured transpulmonary indicator dilution curves of 51Cr-erythrocytes, 125I-albumin, 14C-urea, and 3H-water before and six and 24 hours after operation in seven patients undergoing aortocoronary bypass (ACB) and eight patients undergoing mitral valve replacement (MVR). We calculated cardiac output (CO), extravascular lung water (EVLW), the difference between 125I-albumin and 51Cr-erythrocyte distribution volumes (EV albumin), the difference between 14C-urea and 51Cr-erythrocyte distribution volumes (EV urea) and 14C-urea extraction (E) and permeability -surface ares (PS) products. Comparisons between 16 ACB studies and 17 MVR studies showed the MVR group to have a higher EVLW (P less than 0.01). ⋯ We conclude that patients with mitral valve disease have an increased distribution volume and E for urea, probably due to hemodynamic changes but possibly due to increased vascular permeability. Extravascular lung water decreases after cardiac surgery regardless of the type of operation. A single intravascular indicator is adequate for estimating extravascular lung water in humans.
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The effects of chronic oral vasodilator therapy were studied in a group of patients with refractory congestive heart failure. Fifteen patients were treated acutely with intravenous sodium nitroprusside and sublingual isosorbide dinitrate. After continuous therapy with nitroprusside and isosorbide dinitrate for up to 72 hours the patients were then placed on isosorbide dinitrate and oral phenoxybenzamine. ⋯ During the period of chronic vasodilator administration, no other change in basic therapy with isosorbide dinitrate and phenoxybenzamine (3-21 months), the favorable effects observed acutely were maintained. All patients demonstrated symptomatic improvement with minimal side effects. The beneficial hemodynamic responses that are noted with acute vasodilator therapy in patients in advanced congestive heart failure are maintained with oral therapy on a chronic basis.
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Mitral valve motion and pressure correlates of the Austin Flint murmur (AFM) were investigated in nine patients with aortic regurgitation using high fidelity catheter tip micromanometers and the mitral valve echocardiogram (MVE). External phonocardiography demonstrated a mid-diastolic murmur (MDM) in eight subjects and a presystolic murmur (PSM) in five. Maximum intensity of both AFM components was found in the left ventricular (LV) inflow tract; the murmur was not recordable in the left atrium (LA). ⋯ In two patients, LV inflow phono showed the MDM to begin 80-120 msec after the aortic second sound and during the D to E phase of the MVE. The rate of early diastolic mitral valve closure in patients (152 +/- 24 mm/sec) was not significantly different from 13 normals (232 +/- 10 mm/sec). With regard to the genesis of the AFM, the present study concludes: 1) diastolic mitral regurgitation plays no role, and 2) antegrade mitral valve flow is required but simultaneous retrograde aortic flow may also be necessary.